Hydraulic press



Oct. 21, 1952 H, PURCELL 2,614,488

HYDRAULIC PRESS Filed April 7, 1947 s Sheets-Sheet 1 FIG. 42

2 2 x 56 40 I 39 J 5 8 I 8 v fl 33 I8 I 2o 43 flf: 2 22 I Q \/I 1 a 33 l3 l5 I7 24 H- 23 INVENTOR HOWARD M. PURGELL r ATTORNEYS H. M. PURCELL HYDRAULIC PRESS Oct. 21, 1952 3 Sheets-Sheet 2 Filed April 7, 1947 INVENTOR HOWARD H. PURGELL /0!On4lvvf/fiaun ATTORNEYS Oct. 21, 1952 PURCELL 2,614,488

HYDRAULIC PRESS Filed April 7, 1947- 3 Sheets-Sheet 5 u in '0 IO IO INVENTOR HOWARD M. PURGELL M s m Q ATTORNEYS Patented Oct. 21 1952 Howard-M w H P Purcell} Mount .Gilead, ,0hi0; assignon V Development G.orporation,. .W1h nii1g;-

ton, net-, corporation of. Delaware Applicationflprilffl, 1947 ,TSerial' No;"7139;917

3. Cl'aiinsi (Cl. 100 -269);

The. present: invention. relates to hydraulic presses. and,', especially, to. hydraulic. presses for use in small'shops, laboratories andthelike:

It. is. an object of, this. invention to provide a hydraulic. press. which .will' be simple in .construction,.. easy to operate andhighly' economicali'in operation.

It is a further object to provide a hydraulic press. which, while. operable .manua1ly, will. per"- form. anfastlworkingcycle;

A .stilllfurther. object; of the. invention. consists inthe provision of. a..hydra'ulic;press of the above mentioned. type whi'chmay; selectively, be, opere atedby amanually operable? pump or'by a'im'otor driven.pump..

Itis :als'o an object .of this. invention to. provide a laboratory type pressinwhichtheclosing. speed maybe. varied. andwhi'ch closes. by gravity;

Still. another object of. thi's'inve'ntion isto. pro,- vide a press construction. for laboratory'presses and the like in which the. reservoirs and. hydraulically actuated ram. are entirelyconcealed within the. press bedl These and other. objects" and. advantages. of

the. invention will appear more. clearly from the following, description;inconnection with-the ac..- companying drawingsinwhich: v I Figure. '1. is. apartiall. transverse. section. taken through .the press. of, the presentinvention;

i Figurezisa section .taken along. the line.-.2 -2 ofFigure. 1; c

Figure. 3' represents. a, diagrammatic, showing of the.- press according. to the invention and; of. a hydraulic circuit therefor.

General outlir've A press constructed according to the present invention. consists primarilyv of a bed-having. a stationary platen on the top. thereof anda. movable platen .positioned over the stationary platen. Strain. rods. areconnected. with the movable platen and. extend downwardly. intoathe :bed with.- iniwhich. they are connected with. av platform. The aforementioned platform.hasmounted thereon: a cylinder which opens. upwardly-l to receive a. double.- acting ram. secured to l the stationary platen: and. extending downwardv therefrom. A

suitablesea'lingjmeansis-provided aroundithesupward. open end .of the cylinder so that it forms with the aforementioned ramadvancing: and re.-

tractingmean's. I p p A-reservoir is also carried .by-said. platform and surrounds the cylinder; and opens? upwardly so that anyrleakageof fluid.fromthezcylindervflows .jbmeravity directlm-intothe:reservoir;

stiucturaliarrdngem'ent".

Referring now-- to the. drawings detail, the

structure described therein comprises a frame generally designated- Hl which has-"- movably mounted therein a; platfrom ll whichin its turn carries four'strainrod'se Thesest'rain' rods; [2 may be fastened to the platform- H in any desired manner; the particular structure shown in=the drawings the strain rods ['2 pass through the platform H and are provided With== athread l3' enga'ged bylocking nutsl4 and-1'55 The strain rods l2 are slid'ably mounted in and guided{ by bushings 8- threaded into theprese frame and secured theretoby lock nuts lv I connected in any: convenient: manner to the platform Hi is; a-.. fluid: reservoir. on .tankeifi.

Spaced-2 from: their innerwalh of; the; tank: [6 but inside said; tank; and connected to: the 1 platform [it 18:31". cylinder 1,-1; the bottom .oiwhich iSziQrmed by; the. platform-. H while. the;uppe r..*end- 01131116 cylinder- H is. formed. by. aziring; |.8.-v Extending through .thering. 1.8. and rigidly, connectedato the pressjrame in. any convenienttmanner isaiglungr er: I.9"providedwith.twobores 21!;and 2-1,

rrhe bore, 20' communicates. with) the. ai liners cal space 22: provided between, the cylinder; III and they outer'wall'of the plunger'l81j Thjbore and through a; piston 2 3 which is-comi-ectedto the plunger [ii -and which; either'it'self prevents connection of the cylindrical space- 2 2 with the bottom of the cylind'erl orwhi'ch may "be pro- .videldi with: pistoni rings; on the: line to -prev'ent .suc

communications. In. the construction shown; the pistonlfi; firmly iheldnagainstzthe plunger-.19 by=meansrof a: nut: 24;,. :Iherupper end of. the; bore 20. communicatesi with: conduitxZS l ad g; to. a pr s ure auge: 2 65.. Also communicating with the conduit 25:15:: a-.condui.t. 2m hBZVsing a branch line 28 leadinggto asmanuad-lym adapted to engage a ball 35, which in its turn will close off communication of the branch line 28 with a conduit 36 when the ball is in its right hand end position with regard to Figure 3. In this instance fluid communication is established between the conduit 36 and the conduit 31. On the other hand, when the ball 35 engages the seat 38, fluid communication between the conduits 36 and 31 is prevented while fluid communication is established between the conduit 28 and the conduit 36. The conduit 36 communicates with the up'perportion of the bore 21. A spring 35a is effective to urge the ball 35 toward the seat 38 for a, purpose to become hereinafter more apparent.

Arranged on top of the plunger 19 and connected to the press frame in any convenient manner is a platen 39 adapted to carry a die 46 for cooperation with the die 41, which latter is connected to the movable bed 42 carried by the upper ends of the strain rods l2.

The press according to the present invention is furthermore provided with a hand-pump generally designated 43. This pump comprises primarily a casing 44 with a central bore having a larger section 45, a medium section 46 and a smaller section 41. A spring 48 has its lower end resting in the medium section 46, whereas the upper end of the spring 48 engages a piston 49 and continuously urges the latter upwardly against a panel 58. The panel 58 carries a support 5| to which is linked by means of the pivot 52 a link 53. The link 53 is connected by means of a pivot 54 to a lever arm 55 having connected thereto a handle 56 and being linked by pivot 51 to a plunger '58. The plunger 58 has a section 58a of a diameter somewhat larger than that of the lower section 581). In this way, downward movement of the plunger 58 will cause the section 58a to abut the plunger 49 which latter will .then move downwardly against the thrust of spring 6| which continuously urges the valve. ball 82 upwardly so as to prevent communication between the duct 59 and the duct 60. The duct 60,communicates through a duct 63 with a port "64 in the pump casing 44, the port 64 communicating in its turn with the conduit 21. Arranged in the conduit 21 is a check valve 65 which opens .onlyin the direction of'the arrow A. Similarly,

a check valve 66 is providedinthe conduit 31 and .opensonly in the direction of the arrow B. A flexible conduit 68 is connected with the tank at .theibottom thereof and leads to the conduit 31 thereby supplying make-up fluid to the lower end of cylinder l1 during the closing of the press, and conveying exhaust fluid to the the opening of the press tank during oped by the pump is substantially greater.

Operation It may be assumed that the press is open as shown in Figure 1 and that the ball 35 of the valve 29 is in its right hand position to close off communication between the conduits 28 and 31. It will be apparent that at this time the fluid in the upper end of the cylinder 11 is trapped by the ball 35 and the check valve 65 so that the upper platen is stationarily supported.

To bring about a closing movement of the press, the operator actuates the handle 33 to retract the extension 34 from the ball 35. At this time the spring 35a and the pressure standing in the upper end of the cylinder l1 act to move the ball 35 leftwardly. The conduit 28 is thereby opened and the weight of the press parts causes the movable platen 42, the strain rods 12, the

platform II and the cylinder l1 to move downwardly. It will be apparent that the rate of this downward movement can be controlled by the operator by manipulating the handle 33 to posl tion the ball closer or farther from the end of the conduit 28.

During the closing movement of the press by gravity, fluid is supplied to the lower end of the cylinder l1 from the reservoir I6 through the flexible conduit 68, the conduit 31, the valve 29 and the conduit 36 and bore 21.

When the press is completely closed and the movement thereof is halted by engagement of the work piece by the die or mold mounted on the movable platen, the working stroke of the press is instituted by actuation of the pump 43.

At this time the handle 33 of the valve 29 is actuated to permit the ball 35 to" seat against the seat 38. It will be notedthat the spring 35a accomplishes this seating. I

During the first part of the working stroke of the press at which time the resistance encountered may not be very great, the handle 55 of-the pump 43 is oscillated below its Figure 3 position. Downward movements of the handle move the piston 49 and the plunger 5% downwardly to expel fluid through the check valve 65 into the by the press increases to the point where it becomes difiicult to move the lever 55' a further working movement of the press may be had by oscillating the said lever above its Figure 3 position. This will allow the piston 49 to remain idle and the entire pumping action will be by the plunger 58b. The plunger 58b being substantially smaller than the combination of plunger 58b and piston 49, the pressure which can be devel- The arrangement thus provides for a variable speed closing stroke, a high speed initial working stroke, and a final high pressure working stroke.

After the work in the press has been completed, the handle 33 is rotated so that the extension 34 moves the ball 35 to the right and again closes off the end of conduit 28. The lower end of the cylinder I1 is now connected directly with the reservoir l6 while the upper endis connected in closed circuit with'the pump 43.

5. the press will remain open and ready for a new cycle of operation.

It will be noted that any leakage from the upper end of the cylinder I1 flows directly back to the reservoir l6 and that the reservoir l8 and the ram l9 are completely enclosed within the press bed. This results in a very neat arrangement and one in which the hydraulic fluid and the highly polished hydraulic ram are at all times protected from dirt and other foreign particles.

It will be understood of course that the present invention is by no means limited to the particular construction shown in the drawings and the particular field of employment referred to in the specification, but that this invention also composed unequal pressure areas, first conduit means extending through said plunger and communicating with one of the pressure areas of said cylinder means, second conduit means extending through said plunger and communicating with the opposite pressure area of said cylinder means, pump means, and valve means having connections respectively with said pump means and each of said conduit means and operable selectively to hydraulically connect the opposite pressure areas of said cylinder means simultaneously with said pump means or for connecting only one of the pressure areas of said cylinder means with said pump means.

2. In a hydraulic press, a stationary horizontal platen. a double acting ram. connected with and extending downwardly from said stationary platen, a cylinder receiving said ram and forming therewith an upper pressure chamber and a lower pressure chamber having a pressureresponsive face larger than that of said upper pressure chamber, a platform carried at the lower end of said cylinder, a movable platen positioned above said stationary platen, strain rod means connecting said movable platen and said platform, a reservoir surrounding said cylinder and mounted on said platform and opening upwardly to receive fluid leakage from said cylinder, and

' valve means connected with said upper pressure chamber and movable selectively to entrap fluid therein for stationarily supporting said movable platen above said stationary platen or to exhaust fluid therefrom for permitting the descent by gravity of said movable platen, said valve means being adjustable to control the rate of descent of said movable platen.

3. In a hydraulic press, a horizontal stationary platen, a double acting ram extending downwardly from said stationary platen, a cylinder receiving said ram and defining therewith upper and lower pressure chambers, the lower pressure chamber having a pressure-responsive area. greater than that of said upper pressure chamber, a platform carried by said cylinder, strain rod means connected with said platform and extending upwardly through said stationary platen, a movable platen carried by said strain rod means above said stationary platen, a reservoir surrounding said cylinder and mounted on said platform and opening upwardly, pumping means connected to supply fluid under pressure to both of said pressure chambers, and Valve means connected between said pressure chambers, said reservoir, and said pumping means, and movable selectively into a first position to connect said upper pressure chamber with said pumping means while connecting said lower pressure chamber with said reservoir, a second position to interconnect said pressure chambers and said reservoir, and a third position to connect both of said pressure chambers with said pumping means. I

HOWARD M. PURCELL:

REFERENCES CITED The following references are of record in the I file of this patent:

UNITED STATES PATENTS 

